Experimental investigation on dynamic model testing of a deep-water Riser Support by truncated hybrid method

Abstract

A device Riser Support is designed for Chinese S-Lay vessel ‘HYSY-201’. The device is used to install risers as well as subsidiary structures, such as pipeline end termination (PLET), pipeline end manifold (PLEM), in-line sled (ILS) and so on for submarine pipelines. The paper mainly elaborates the finite element analysis and dynamic experiment of the deep-water Riser Support based on a truncated hybrid model. To test the mechanical property and verify the reliability of the Riser Support, some dynamic tests with the scale 1:10 are done to simulate the installation process of risers in the South China Sea. A truncation method is used to solve the problem that 3000 m riser model is still too long though it is reduced to one-tenth of the original size. Six degrees of freedom platform (SDFP) is used to simulate the movement of ‘HYSY-201’ vessel while a boundary control system (BCS) is also used to control and simulate the motion state of cut-off point of the riser model. SDFP and BCS together make the model test more accurate and reliable. Testing results show that stress values based on 24 kinds of typical working conditions and calculated values are accordant in the range of allowable inaccuracy, but the small error is considered reasonable because of the difference between virtual model and scaled reality model. Then, truncated hybrid method is verified to be very useful in simplifying models during the research of large-size thin tube, rod-shaped or linear model experiment, and especially the 3000 m truncated dynamic hybrid riser model experiment is a good example.